Studies on the control of environmental bacterial flora for mass production of food microalgae

1)细菌共存对海洋硅藻生长的促进作用从硅藻大量培养池中分离出12株细菌，分别加入到硅藻的轴向培养中，只有一株细菌Fravbacteria sp.对硅藻的生长有极大的促进作用。在室内用5个L瓶大量培养3种海洋微藻(纤细螺旋藻、球等鞭金藻和巴甫洛瓦微藻)的实验中，接种时将该菌株与微藻一起接种。大型藻类的最大细胞密度显著高于对照，且生长持续期明显长于对照。2)一批氯化钠特级试剂中的污染物对所谓的海洋小球藻种群生长的抑制作用和细菌菌株共存的影响。这些污染物质被明确为相对分子质量小于500的有机物质。如果将该藻与细菌株Fravbacterium sp.一起培养，它在另一批氯化钠制备的ASP6中也能稳定生长。这一事实告诉我们，该菌株对这些污染物具有特殊的吸附或吸收能力。

1) Growth promoting effects of bacterial coexistence on marine diatom Chaetoceros gracilisWhen each of 12 bacterial strains isolated from diatom mass culture tanks, was added into the axnic culture of the diatom, Chaetoceras gracilis, only one strain, Fravobacterium sp.greatly promoted the diatom growth. In practical mass cultures of three marine microalgae (C.gracilis, Isochrysis galbana and Pavlova Iutheri) using 5 l flasks in indoor culture system, this bacterial strain was inoculated together with the microalgae at the inoculation. The maximum cell density of macroalgae was significantly higher than that in the control culture, and the stationary growth phase lasted longer than that of control.2) Growth-suppressing effect of the contaminated substances in one lot of NaCl special grade reagent on the population growth of so-called marine Chlorella and the elimination of the effect by the coexistence of bacterial strain.I cultured so-called marine Chlorella Nannochloropsis oculata in ASP6 medium prepared by some lots of NaCl special grade reagents, and then found one lot which did not support the algal growth. This contaminated substances were made clear as the organic substnces having less than 500 molecular weight. If the alga was cultured together with the bacterial strain Fravobacterium sp., it grew steadily as well as in ASP6 prepared by another lot Nacl. This fact tells us that this bacterial strains has the special ability for adsorption or absorption of these contaminated substances.